Lens Testing The Sigma 12-24 Photo Gallery by benhua at pbase.com

Lens Testing The Sigma 12-24

Stan Bonis was kind enough to loan me his new Sigma 12-24 lens for some testing. I didn’t have time to shoot any “artsy” photos with it, nor did I shoot anything to show the considerable barrel distortion. Hey it’s a 12mm lens. The lens does vignette, but not as bad as I expected. Remember all these tests are shot on a 10D with its 1.6X crop factor, so the lens is not pushed to the limits by my testing.

The observable quality of construction is very good by today’s standards. I am not really happy about any of the modern plastic body lenses with their silk screened lettering and numerals. My old Nikor lenses were finely machined, anodized aluminum and brass with engraved letters and numbers. I didn’t know what I had. Gone with the wind.

The 12-24 is not super sharp but it is not bad either. For a 12mm lens and zoom to boot, it is fantastic. Not many lenses are as sharp as my Canon 50mm macro or my 135 f/2 L. The 12-24 never gets very sharp at any f/stop but shoots about the same at all f/stops until f/22 where the effects of diffraction becomes obvious. The Sigma, wide open, is a lot sharper than my Canon 35mm f/2 at its widest aperture, and the 35 doesn’t match the 12-24 until about f/5.6 or f/8. The 35mm f/2 never does walk away from the Sigma, and that surprised me!

Hear's the kicker, the lens is not appreciably softer at the edges compared to the center. It is a little but not much, and not at all what I would expect from a super wide angle zoom lens.

Oh yes---If you think your 24-70L is the cats meow then take a look at how sorry mine is at 70mm. I couldn’t’ believe what I saw so I ran the test twice. I wonder if I have a bad example of that lens. Hey Stan, I need to check out your 24-70L. My Canon 24-70L makes the Sigma 12-24 look great.

All things considered I am favorably impressed by this particular example of the Sigma 12-24 lens. When I get my example of this lens I will test it out and see if it is as good as Stan’s.

By the way none of the photos were sharpened or adjusted in any way except the one of the kitten in the leaves.

12mm Vignette.jpg	24mm Vignette.jpg	Vignette 12mm Wide Open.jpg	Vignette 24mm Wide Open.jpg
12mm Flair Test 2.jpg	12mm Flair Test.jpg	24mm Flair Test.jpg	Vignette and Sharpness.jpg
Full Target.jpg	Sigma 12mm 4.5_5.6.jpg	Sigma 12mm 5.6_8.jpg	Sigma 12mm 11_16.jpg
Sigma 12mm 16_22.jpg	Sigma 12mm 4.5_11.jpg	Sigma 17mm 5.6_8.jpg	Sigma 17mm 11_16jpg.jpg
Sigma 24mm 5.6_8.jpg	Sigma 24mm 11_16jpg.jpg	Canon 50 Sigma 12-24 24 8.jpg	Canon 24-70L 24 28_4.jpg
Canon 24-70L 24 56_8.jpg	Canon 24-70L 24 11_16.jpg	Canon 24-70L 50 28_4.jpg	Canon 24-70L 50 56_8.jpg
Canon 24-70L 50 11_16.jpg	Canon 24-70L 70 28_4.jpg	Canon 24-70L 70 56_8.jpg	Canon 24-70L 70 11_16.jpg
L Bracket QR 040910_4179.jpg	L Bracket QR 040910_4186.jpg

comment |

benhua		08-Mar-2005 05:47
Hi Lael, I made my test target in Photoshop. You can design and make your own too. Check out the photo that shows my overall setup and then you do something similar in photo shop or one of the simple paint or cad programs. The idea is to get a gradual range of detail from small to large of the same type of object. Small to large “O” s and “X” s with a corresponding id number would be one possibility. Experiment and have fun.

Lael		05-Mar-2005 00:44
Hey! the pics are interesting, I also want to test my copy of the 24-70 - can you tell me where to get the test image you were shooting? Thanks - Lael

benhua		01-Sep-2004 05:28
I think what your seeing Mark is the light fall off at the corners on the Sigma, especially at 12mm. At the wider apertures and 12mm the two corner crops are darker than the center crop. As you noticed the light across the field becomes more even and the crops become more evenly lit as the lens stops down. Yes the aperture vignette relationship is very noticeable in the thumbnails. The 24-70L is well corrected in this regard.

markvm		31-Aug-2004 21:34
Forgot something, from looking at the thumbnails of the charts it looks like the contrast is relatively constant throughout for the 24-70L whereas the 12-24 seems to shift quite a bit. But still, a good looking lens from the results of this test. Mark

markvm		31-Aug-2004 21:30
Bob, thanks for taking the time to do this extensive testing. It appears that the 12-24 is a very capable lens. I wouldn't worry too much about the 24-70 at 24mm f/2.8...every lens has a weakness or two. It's the nature of the beast. If Stan's 24-70L does a better job then a small tune up might be in order. Once again, Thanks. Mark Megerle

Stan Bonis		17-Aug-2004 01:34
Very enlightening! How come the rags don't have this info?

click on thumbnails for full image